First off, I would agree with @radek and @Jakub regarding the SSD. I recently got a new laptop for work, and the only thing that I would do differently would be an SSD. If you don't go with an SSD, then you definitely want to go with a 7200 RPM hard drive, as the 5400 will definitely impact performance.
Here are my specs: Intel Core i7-2630QM - 2.0Ghz - Quad Core - 6MB L3 Cache, 8GB RAM, 500GB 7200 RPM hard drive, 1GB AMD FirePro M5950/Intel integrated graphics
I know that there is some discussion over whether the i7 or any other multi-core processors are really effective for ArcGIS, since it does not support multi-threading, but I think it is worth planning for the future. Most people that I know who do GIS, never have just one instance of ArcGIS running at the same time, and so the ability to have each instance running on its own core makes a huge difference. The laptop that I have is the fastest one I've ever used, and I feel that if at 10.1 they start to support more multi-threaded processes, then the performance gains are going to be even more evident. In addition, even if ArcGIS isn't using multiple cores, having them allows you to move all the other software you are using to a separate core from your GIS software, thus improving performance.
I don't really know how much gain in performance you get from the higher level video card, but if you are working with large layers or aerial photography that you are zooming around in, more video power can't hurt.
I think in all, the specs you have are going to allow you to use the laptop for longer, and be able to realize more performance gains as the ArcGIS software is slowly upgraded to be able to take more advantage of the 64 bit architecture and/or multi-threading. It will simply push your timeline for replacement further into the future, which is good in this time of tight budgets.
Hope this helps.